(Dichloromethyl) substituted pyridines are known compounds which find utility as pesticides for the control of plant, insect and fungal pests, among others, and as intermediates for preparing compounds having the above utilities. Representative patents which teach such uses include U.S. Pat. Nos. 3,420,833; 3,591,596; 4,062,962 and 4,143,144.
Various derivatives of phenoxypyridine, such as the compounds made from cyano(6-phenoxy(or substituted phenoxy))-2-pyridine methanol, are useful as pesticides. One method of preparing this class of compounds is through an intermediate derivative of alpha-(dichloromethyl)pyridine which is conveniently prepared by reducing the corresponding trichloromethyl derivative.
(Dichloromethyl) substituted pyridines have been prepared from (trichloromethyl) substituted pyridines by a variety of procedures. A few of these procedures include, for example, dehydrochlorination over a palladium catalyst in the presence of formic acid, electrolytic reduction and reductions employing either zinc or stannous chloride with hydrochloric acid and the like. Another method is taught in U.S. Pat. No. 4,260,766 wherein the reduction is conducted with metallic iron or a ferrous iron compound. The prior processes, while producing the desired product, have not found wide success because of one or more shortcomings such as expense of reagents, slow reaction rate, poor selectivity to the desired product or the difficulty in treating waste streams for recycle and/or disposal. The present invention is a process for carrying out the reduction with greater flexibility and specificity than that found using conventional reducing agents.